1. Field of the Invention
The present invention relates to a receiving apparatus which receives a television broadcast.
2. Related Background Art
In recent years, according to a start of CS digital broadcast or BS digital broadcast, multi-channeling of television broadcast has been advanced. According to such a multi-channeling, attention is paid to a multi-picture screen display function serving to display a plurality of television programs on a large-sized screen of a television broadcast receiving apparatus.
A problem rising when multi-picture screen displaying is performed is one regarding audio. That is, even if audios of respective programs are outputted simultaneously while the multi-picture screen is being displayed, it is difficult to recognize respective audios. Therefore, it is common to select one of audios of a plurality of programs which are being displayed in a multi-picture screen manner, and output it.
Further, as one displaying aspect of multi-picture screen displaying, there is a technique that one of a plurality of programs being displayed simultaneously is displayed largely as a main picture screen and the remaining programs are displayed as child picture screens. In this case, when a constitution is employed that the audio of one program is selected and outputted like the above, only the audio corresponding to the main picture screen is outputted, but the audios corresponding to the child picture screens are not outputted.
At this time, it is possible according to an instruction of a user to perform switching between a program of the main picture screen and a program of one of the child picture screens or perform switching only in audio between the program of the main picture screen and the program of the one of the child picture screens.
Techniques for selectively switching audios while performing a multi-picture screen displaying in this manner have been disclosed in JP-A-05-113864 (corresponding to U.S. Pat. No. 5,666,555) and the like.
Further, according to advance in a recent resolution conversion technique, it becomes possible to change according to a user's preference a size of a displayed screen of a program watched or a ratio of sizes of respective picture screens when a multi-picture screen is displayed. In this case, it is inconvenient to control the picture screen size and the volume independently from each other. In view of this, in JP-A-03-186076, there is disclosed a technique for changing a picture screen size and a volume in linkage with each other.
Thus, it is possible to perform by a user operation such an operation as switching between a main picture screen and one of child picture screens or changing a picture screen size when a multi-picture screen is displayed.
However, in case that a user is watching a multi-picture screen, such a case often occurs that he/she does not notice a decisive scene or an important scene of a child picture screen program (program on different channel), because he/she generally pays attention almost to a main picture screen. Therefore, there is a problem that a user does not perform switching between the main picture screen and one of the child picture screens to overlook an interesting scene of the child picture screen program.